Editing Trimix (breathing gas) (section)

==Advantages of controlling the oxygen fraction==
Lowering the oxygen content of a breathing gas mixture increases the [[maximum operating depth]] and duration of the dive before which [[oxygen toxicity]] becomes a limiting factor. Most trimix divers limit their working oxygen partial pressure [PO<sub>2</sub>] to 1.4 bar and may reduce the P<sub>O<sub>2</sub></sub> further to 1.3 bar or 1.2 bar depending on the depth, the duration and the kind of breathing system used.<ref name="Brubakk" /><ref name="gernhardt" /><ref name="Acott" /><ref name="Gerth2006" /> A maximum oxygen partial pressure of 1.4 bar for the active sectors of the dive, and 1.6 bar for decompression stops is recommended by several recreational and technical diving certification agencies for open circuit,<ref name="Lang2001" /> and 1.2 bar or 1.3 bar as maximum for the active sectors of a dive on closed-circuit rebreather. Increasing the oxygen fraction in a trimix to be used as a decompression gas can accelerate decompression with a lowered risk of isobaric counter diffusion complications.